docs: def consume_item(rlp, start):
      """Read an item from an RLP string.
  
      :param rlp: the rlp string to read from
      :param start: the position at which to start reading
      :returns: a tuple ``(item, per_item_rlp, end)``, where ``item`` is
                the read item, per_item_rlp is a list containing the RLP
                encoding of each item and ``end`` is the position of the
                first unprocessed byte
      """
      p, t, l, s = consume_length_prefix(rlp, start)
      return consume_payload(rlp, p, s, t, l)